The present invention relates to a cooking operation control system in a cooking utensil including at least two sensors, for example, a thermistor and a gas sensor.
Various kinds of sensors are proposed to control the cooking operation in a cooking utensil such as a combined microwave and electric heating cooking oven. For example,
(1) a thermistor is disposed in an exhaustion duct for detecting an exhaustion air temperature;
(2) a humidity sensor is disposed in an oven cavity or in an exhaustion duct for detecting a humidity in the oven cavity; or
(3) a gas sensor is disposed in an exhaustion duct for detecting an exhaustion gas concentration.
The thermistor and the humidity sensor can not detect the browning condition and, therefore, the thermistor and the humidity sensor are not suited for controlling the grill operation. The gas sensor is suited for controlling the grill operation, but the gas sensor will erroneously develop an output signal in an abnormal condition when, for example, alcohol is positioned near an air inlet of the cooking utensil. Moreover, the gas sensor output is dependent on the initial condition of the foodstuff being cooked and the amount of the foodstuff disposed in the oven cavity.
Accordingly, an object of the present invention is to provide a novel cooking operation control system in a cooking utensil.
Another object of the present invention is to provide a cooking operation control circuit for a combined microwave and electric heating cooking oven.
Still another object of the present invention is to provide a cooking operation control circuit in a combination microwave and electric heating cooking oven including a thermistor and a gas sensor.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a thermistor and a gas sensor are disposed in an exhaustion duct of a combined microwave and electric cooking oven for detecting a cooking condition. When both of the thermistor output and the gas sensor output exceed preselected reference levels, a microwave generation operation or a heater cooking operation is terminated to complete the cooking.